Circuit breaker



Feb. 4, 1941.. E, VLKER ET AL 2,230,277

.CIRCUIT BREAKER Filed June 21, 1958 f-vlef FOI Profes we Gew Patented Feb. 4, 1941 UNITED STATES PATENT OFFICE CIRCUIT BREAKER tiengesellschaft Hauptverwaltung,

Berlin- Charlottenburg, Germany Application June 21, 193s, serial No. 214,996 In Germany June 23, 1937 7 Claims.

'I'his invention relates to an electric circuit breaker or switch for rooms in which combustible mixtures of air and gas vapours, dust or the like are present, for example, in mines, chemical factories, mills and the like.

It is the object of the invention to construe the circuit breaker in such a manner that any sparks which may possibly occur inthe switching action cannot ignite the combustible mixture.

Another object of the invention is to provide circuit breakers of the kind referred to which are very simple, cheap and compact.

Withthese and further objects in View which will hereinafter appear, the invention consists not only of the structures herein pointed out and illustrated by the drawing but relates to further structures as hereinafter may be claimed.

The character of .the invention, however, may be best understood by reference to one of its structural forms, as illustrated by the accompanying drawing showing an axial section of a plug and socket connection having the invention applied thereto.

Referring to the drawing, the plug socket I is surroundedby a exible cover, for example, a corrugated tubular body 2 of resilient material, for instance, a metal bellows, secured to a base plate 3, through which the cable 4 is introduced by means of a packing 5. The tube 2 is provided with a top closure plate 6 which is formed with a flange having exterior thread and an interior collar for reception of a packing 1. 'I'he plug unit 8 is also tted with a packing III to introduce the cable 9. By means of an interiorly threaded member I I the plug unit 8 can be tightly pressed against therpacking 1. The whole unit is surrounded by a protective casing I2. In order to position the plug contact pins 2l with respect to the contact sleeves 25 in the plug socket, a nose I3 of plate 6 is provided to be guided in a slot I4 of the casing. Moreover a key 26 may be provided between the plug unit 8 and the closure plate 8 to ensure correct relative position of the said parts. In order to prevent the plug from being inserted into the plug socket without the threaded member I I being tightly screwed down, one or more spring actuated locking members I5 are provided, for example, at the wall of the protective casing I2 which locking members are pressed aside by screwing down the member II, to such an extent that the cover plate 6 may pass and the plug unit be inserted into the plug socket. In order to lock the plug in this position, one or more similar locking members 22 may 'be provided which by engagement with slots 2l' retain .(Cl. 20D-168) the cover plate in its lower position and are adapted to be released by depressing their knobs 23, if the coupling is to be disconnected.

The portion of the device including casing I2, plate 6, tube 2 and the plug socket I comprises a current outlet connection adapted to receive plug units from various appliances. In the preferred form of our invention, therefore, socket I is secured to the base plate 3 and to the casing I2 as a xed assembly, and the plug unit 8 together with the member I I is removable and interchangeable with similar plug units and insertable in other socket assemblies similar to that shown. The plug unit 1s removed, after disconnection from socket I within the enclosure, by unscrewing member II which frees the plug unit 8, key 26 being movable therewith in a slot in the flange on plate 6.

Upon reinsertion of a plug unit 8, the key 26 is first aligned with its slot and the unit is then clamped against the packing 'I by screwing down member II. Closure of the connections between pins 2l and sleeves 25 is prevented by stop I5 until member I I has been sufficiently tightened to seal the mounting of the plug unit at packing 1 and displace the locking member I5. The plug unit 8 is then free to be depressed for connection of pins 2'I in sleeves 25 within the air-tight enclosure aorded by the tube 2 and the otherwise sealed openings. The apparatus of our 'invention may be employed in the form thus described or may also be provided with means for introducing an inert preventive gas within the enclosure as hereinafter described, for greater safety.

It will be understood that by the said construction of the device, a perfectly closed space is formed within the cover 2 which does not permit any gas mixtures to enter. Of course, it might occur that a mixture is already present in the said space when the plug is inserted which might be ignited within the cover and possibly cause explosion of the device whereby further vapours in the surrounding atmosphere might be ignited. In order to prevent that, the space within the cover 2 may be connected to a supply duct I6 for compressed air or protective gas so as to feed fresh air or protective gas to this space and force the explosive mixture out through a blowolf valve I1. A valve I8 under action of a spring I9 mayserve to shut 0E the supply duct I6 in the non-operative condition of the device and to admit air or protective gas only when the plug is inserted, by depression of an upwardly extending rod 20 on the valve I8 co-actlng with a. downwardly extending rod 2| on plate 6. Valve I8 also prevents release of the protective gas While interchanging plug units 8, during which time the opening in plate 6 is uncovered.

While we have herein shown and described certain preferred embodiments of our invention, we wish it to be understood that we do not confine ourselves to all the precise details herein set forth by way of illustration, as modification and variation may be made without departing from the spirit of the invention or exceeding the scope of the appended claims. v

We claim:

1. A separable connector comprising, in combination, an'electrlc plug unit, at least one contact part at said plug unit, a socket unit, at least one coactixg contact part at said socket unit, a

corrugated tubular cover surrounding said socketunit and adapted to enclose the coacting contact parts air-tightly, a threaded ange on said cover, an. interiorly threaded member and a packing on said threaded ange for detachably and airtightly connecting one of said units to the cover, means for xedly securing said cover to the other of said units, and means connected with the last said means for preventing twisting of said tubular cover, said contact parts being engageable and disengageable within said cover, andssaid unitsy being separable upon disconnection of said threaded flange and said threaded member.

2. A separable connector comprising, in combination,Y an electric plug unit, at least one contact part at said plug unit, a socket unit, at least one coacting contact part at said socket unit, a corrugated tubular cover surrounding said socket unit and adapted to enclose the coacting contact 'parts air-tightly, a threaded iiange on said cover, an interiorly threaded member and a packing on said threaded flange for detachably and airtightly connecting one of said units to the cover, means for xedly securing said cover` to th other of said units, means for preventing twisting of said tubular cover, and means for permitting insertion of the plug into the socket only after said cover has been tightly secured to saiddetachable Vparts air-tightly, a threaded flange on said cover,

an interiorly threaded member and a packing on said threaded ilange for detachably and airtightly connecting one of said units to the cover, means for xedly securing said cover to the other of said units, means for preventing twisting of said tubular cover, means for permitting insertion of the plug into the socket only after said cover has been tightly secured to said detachable unit, and a releasable locking member for retaining said plug in said socket.

4. A separable connector comprising, in comf bination, an electric plug unit, at least one contact part of said plug unit, a socket unit, at least one coacting contact part at said socket unit, a corrugated tubular cover surrounding said socket unit and adapted to enclose the coacting contact f parts air-tightly, a threaded flange on said cover,

an interiorly threaded member and a packing on said threaded flange for detachably and airtightly connecting one o1 said units to the cover, means for flxedly securing said cover to the other of said units, means for preventing twisting of said tubular cover, means for permitting insertion of the plug into the socket only after said cover has been tightly secured to said detachable unit, a releasable locking member for retaining Y said plug in said socket, a pressure relief valve in said cover and means for supplying inert gas under pressure to the enclosure provided by said cover.

5. A separable connector comprising, in combination, an electric plug unit, at least one contact part at said plug unit, a socket unit, at least one coacting contact part at said socket unit, a corrugated tubular cover surrounding said socket unit andA adapted to enclose the coacting contact parts air-tightly, a threaded flange on said cover, an interiorly threaded member anda packing on said threaded flange for detachably and airtightly connecting one of said units to the cover, means for xedly securing said cover to the other of said units, means for preventing twisting of said tubular cover, means for permitting insertion of the plug into the socket only after said cover has been tightly secured to said detachable unit, a releasable locking member for retaining said plug in said socket, a pressure relief valve in said cover, means for supplying inert gas under pressure to the enclosure provided by cover, a control valve in the last said means, and means for open ing said control valve automatically when said plug is inserted into said socket;

6. In a separable plug and socket electrical connector, the combination of a socket member having terminals therein, a plug member having terminals for coacting with the socket terminals,

a non-porous resilient cover lxedlysecured to one.

of said members in air-tight relation and having an opening therein opposite the terminals in the said member, the peripheral edge of said opening being engageable by the other of said members with the terminals thereof aligned for engagement with the coacting terminals opposite said opening, means for detachably connecting the last said member and said cover in air tight relation with said coacting terminals in disengagement, said resilient cover being exed for engaging and disengaging said coacting terminals within the air tight enclosure provided by said cover and said members, and stop means engaging said cover and controlled by the last said means for permitting flexing of said cover and engagement of said coacting terminals only after said cover has been air tightly connected with the detachable member.

'1. In a separable plug and socket electrical connector, the combination according to claim 6 with said means for detachably connecting member and cover in air-tight relation comprising a threaded ang'e on said cover, aI packing in said flange, and a coacting threaded member for pressing the said detachable member air tightly against said packing.

KURT KOBLIGK.

EM'IL VLKER. 

